1. Field of the Invention
The present invention relates to a driving device for a zoom lens barrel in a camera.
2. Description of the Related Art
A zoom lens barrel of a camera is often provided with various types of rotational cylinders to carry out zooming or focusing operation. In the lens barrel which the applicant has been developing, a driving force is transmitted to a rotation cylinder engaging the inner wall of a movable lens barrel to cause the rotation cylinder to move forward and backward in a direction of an optical axis through a rotation shaft in the movable lens barrel which is linearly guided in a direction parallel to the optical axis and a pinion which slidably fits on the rotation shaft in an axial direction of the shaft. However, since the pinion is movably supported on the shaft and moves in accordance with the movement of the rotation cylinder in the optical axis direction, it is difficult to support both end portions (front end and rear end) of the shaft by a common member or members which do not have a relative movement therebetween due to limited space. If the rotation shaft is unstably supported, there will likely be a loss in efficiency of the pinion for transmitting rotation.